The security system that should have prevented anyone from boarding a U.S.-bound flight with explosives obviously failed if all that's been reported about what happened Friday as Northwest flight 253 approached Detroit is true, Homeland Security Secretary Janet Napolitano conceded this morning.

"Our system did not work in this instance," Napolitano told NBC's Matt Lauer on The Today Show:

Visit msnbc.com for breaking news, world news, and news about the economy

Yesterday, on CNN's State of the Union, Napolitano said "the system worked":

This morning, she told Lauer that she had previously been referring to the system that went into action after Friday's incident.